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Industrial wastewater control by evapoconcentration

Type of discharges treated:

1. Detergent baths used in the industrial cleaning and surface preparation sector

2. Wastewater from cleaning soil.

In the watch industry and micromechanics sector, these discharges are characterised by a high load of surfactants, high values of chemical oxygen demand as well as the presence of heavy metals in the solution from the substrates treated (copper, nickel, chromium, titanium zinc, lead, etc.).
Due to their composition, these discharges are difficult to manage using conventional physical-chemical pre-treatment methods (coagulation/flocculation/filtration).

Treatment principle: NGL has chosen to apply MHD (Multistage Humidified cation Dehumidifi cation) technology, inspired by the natural water cycle.


The main benefits:

a. Water distillation at atmospheric pressure to limit the formation of foam, a phenomenon inherent to the nature of detergent discharges
b. Simplicity of the equipment and operation without significant mechanical constraints
c. Chemical resistance of the equipment comprising polymeric materials
d. Energy balance by optimal heat recovery from vapour condensation
e. Important factor for reducing the concentration of pollutants (especially in terms of chemical oxygen demand)

Application example:

  • Treatment of a mixture of used wastewater (cleaning after manufacture of stainless steel, nickel-titanium and brass parts)
  • Treatment goal: ensuring the compliance of the discharge in the public sewer system 1998/2015
  • Required treatment capacity: 5m3/week
  • Concentration factor: 5 Electricity consumption: 165 kWh /m3

Analytical results:



Used detergent baths are usually managed by disposal as special waste. This leads to high operating costs when the volumes to treat increase. To manage a volume of around 1 m3 per day, it is worth investing in on-site treatment equipment. This MHD evaporation technology is also applicable to the treatment of discharges from cleaning soils, present in the metal industry sector.